Evaluation of an immunoassay of whole blood sirolimus in pediatric transplant patients in comparison with high-performance liquid chromatography/tandem mass spectrometry
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Faye B. Vicente
Abstract
Background: Sirolimus is widely used as an immunosuppressant, along with calcineurin inhibitors. Because of its variable pharmacokinetics and narrow therapeutic range, therapeutic drug monitoring of sirolimus is critical to optimize its therapeutic effect and to minimize toxicity. Although liquid chromatography/tandem mass spectrometry is considered the method of choice, the technical and financial challenges of this method are obstacles to its use. A microparticle enzyme immunoassay on the Abbott IMx has recently been reintroduced to the clinical diagnostic market.
Methods: We evaluated this immunoassay using high-performance liquid chromatography/tandem mass spectrometry as the reference method. Precision and carryover were evaluated using an expanded CLSI EP10-A2 protocol. Linearity was studied by serial dilution of high-level whole blood samples, and clinical utility was demonstrated by correlation with the reference method using 56 de-identified pediatric patient samples.
Results: The total imprecision was less than 12% across the concentrations tested. The method was linear from 2.6 to 31nM. The immunoassay showed a mean positive bias of 11.5% in patient specimens relative to high-performance liquid chromatography/mass spectrometry (p<0.001), with a correlation coefficient (R) of 0.953.
Conclusion: We conclude that the reintroduced immunoassay is useful for therapeutic drug monitoring of sirolimus.
References
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©2006 by Walter de Gruyter Berlin New York
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- Preanalytical variability: the dark side of the moon in laboratory testing
- Clinical relevance of biological variation: the lesson of brain natriuretic peptide (BNP) and NT-proBNP assay
- Hepatorenal syndrome
- Modified Levey-Jennings charts for calculated laboratory tests
- Increased free malondialdehyde concentrations in smokers normalise with a mixed fruit and vegetable juice concentrate: a pilot study
- The exponentially weighted moving average (EWMA) rule compared with traditionally used quality control rules
- Intermethod calibration of alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT) results: application to Fibrotest® and Actitest® scores
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- Technical evaluation of the Beckman Coulter OV-Monitor (CA 125 antigen) immunoassay
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- Matrix metalloproteinases and their inhibitors in different acute stroke subtypes
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